Canadian Forest Service Publications

Histopathological examination of western hemlock dwarf mistletoe infected with potential biocontrol fungi. 1999. Deeks, S.J.; Shamoun, S.F.; Punja, K. Canadian Journal of Plant Pathology 21: 200.

Year: 1999

Issued by: Pacific Forestry Centre

Catalog ID: 5252

Language: English

Availability: Not available through the CFS (click for more information).

Available from the Journal's Web site.
DOI: 10.1080/07060669909501213

† This site may require a fee

Mark record


Western hemlock dwarf mistletoe (Arceuthobium tsugense subsp. tsugense) causes reduction in vigor, growth, and wood quality. Potential biological control fungi are being investigated to reduce mistletoe development. Two fungi that parasitize A. tsugense (Nectria neomacrospora and Colletotrichum gloeosporioides) were evaluated using an in vitro screening method. Seeds of dwarf mistletoe were germinated on tissue culture medium (Harvey's medium), while the other half of the plate contained water agar on which fungal growth was initiated from a mycelial plug. Mistletoe tissues were fixed in phosphate buffer with glutaraldehyde 1, 2, 3, 7, and 14 days postcontact with two fungi and prepared for light microscopy. Fungal colonization was mainly restricted to the endosperm and outer cell layers of the radicle, with heavy colonization of the radicle tip. Cushion development, cell wall degradation, and inter-and intra-cellular colonization were evident for both fungi. Experiments are underway to challenge dwarf mistletoe callus with these fungi.